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<TITLE>TSP (audio) - LPanal</TITLE>
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<H2>LPanal</H2>
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<H4>Routine</H4>
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<DT>
LPanal [options] -p PFile -c LPFile AFileI [AFileO]
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<H4>Purpose</H4>
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<DT>
LPC analysis on a speech file
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<H4>Description</H4>
This program does linear prediction analysis on an audio file.  The output
file is a file of linear prediction coefficients and the residual file.
<P>
The steps involved in forming the linear prediction coefficients are as
follows.
<DL>
<DT>
 1: Preemphasize the input signal (first difference filter)
<DT>
 2: Window the data
<DT>
 3: Calculate the autocorrelation coefficients for the windowed data
<DT>
 4: Calculate the LPC coefficients
<DT>
 5: Bandwidth expand the LPC coefficients
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<P>
The steps involved in forming the residual signal are as follows.
<DL>
<DT>
 1: Preemphasize the input signal (first difference filter)
<DT>
 2: Use the LPC coefficients to form the prediction error residual signal.
</DL>
<H4>Options</H4>
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<DT>
Input file name: AFileI:
<DD>
The environment variable AUDIOPATH specifies a list of directories to be
searched for the input audio file.
<DT>
Output file name: AFileO:
<DD>
This name specifies the optional output file containing the linear
prediction residual.  Specifying "-" as the output file indicates that
output is to be written to standard output.
<DT>
-p PFile, --parameter_file=PFile
<DD>
Parameter file.
<DT>
-c LPFile, --lpc_file=LPFile
<DD>
LPC predictor coefficient file.
<DT>
-s, --statistics
<DD>
Print frame-by-frame statistics.
<DT>
-I INFO, --info=INFO
<DD>
Audio file information string for the output file.
<DT>
-h, --help
<DD>
Print a list of options and exit.
<DT>
-v, --version
<DD>
Print the version number and exit.
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<P>
The analysis parameters are read from the parameter file.
<PRE>
  preemphasis_factor = float  ! preemphasis factor (0 to 1, default 0)
  window_length = int         ! analysis window length
  window_offset = int         ! initial offset of the center of the analysis
                              ! window from the center of the frame (negative
                              ! values mean that the analysis window precedes
                              ! frame, default  0)
  window_type = char          ! window type (Hamming or rectangular, default
                              ! Hamming)
  frame_length = int          ! frame size
  LPC_number = int            ! number of LPC coefficients
  LPC_BW_expansion = float    ! bandwidth expansion factor (1 gives no
                              ! bandwidth expansion, default 1)
</PRE>
<P>
By default, the output file contains a standard audio file information
string.
<PRE>
  Standard Audio File Information:
     date: 1994-01-25 19:19:39 UTC    date
     program: LPanal                  program name
     parameters: &lt;parameters&gt;         list of analysis parameters
</PRE>
This information can be changed with the header information string which is
specified as one of the command line options.  Structured information records
should adhere to the above format with a named field terminated by a colon,
followed by numeric data or text.  Comments can follow as unstructured
information.
<PRE>
  Record delimiter: Newline character or the two character escape
      sequence "\" + "n".
  Line delimiter: Within records, lines are delimiteded by a carriage
      control character, the two character escape sequence "\" + "r",
      or the two character sequence "\" + newline.
</PRE>
If the information string starts with a record delimiter, the header
information string is appended to the standard header information.  If not,
the user supplied header information string appears alone.
<H4>Environment variables</H4>
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<DT>
AUDIOPATH:
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This environment variable specifies a list of directories to be searched when
opening the input audio files.  Directories in the list are separated by
colons (semicolons for Windows).
<H4>Author / version</H4>
P. Kabal / v3r0a  2003-11-03
<H4>See Also</H4>
<A HREF="LPsyn.html">LPsyn</A>
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Main Index <A HREF="AFsp.html">AFsp</A>
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